Vehicle with lighting system for tail lights and license plate comprising light emitting diodes and optical waveguide

ABSTRACT

A vehicle fitted with at least one tail light ( 1 ) and a rear license plate ( 8 ) to be illuminated, a light source ( 2 ) for emitting a light beam to a optical waveguide ( 4 ) disposed adjacent the light source is provided, said optical waveguide being provided with an input surface ( 5 ) facing towards the light source for inputting at least part of the light beam from the light source, as well as with at least one output surface ( 6 ) for outputting a light beam that is being passed through the optical waveguide to the license plate and/or the at least one tail light. The light source can be a light emitting diode.

The invention relates to a vehicle fitted with at least one tail lightand a rear license plate to be illuminated.

Such a vehicle fitted with two tail lights and a rear license plate tobe illuminated is generally known. As a rule, the tail lights of theknown vehicle are each fitted with an incandescent lamp of about 5 to 10W, whilst the rear license plate is often illuminated by at least twoincandescent lamps, likewise of 5 to 10 W. As is usual, the tail lightsand the rear license plate lights are turned on and off simultaneously.

One drawback of the known vehicle is the fact that at least fourlow-output incandescent lamps are needed, as indicated above. Because oftheir low output, such incandescent lamps are often not very effective,whilst the installation thereof is laborious and has a cost-increasingeffect.

The object of the invention is to obviate the drawbacks of the priorart, and in particular to provide a vehicle in which the effectivenessof the lamps used for lighting the rear of the vehicle is increased.

In order to accomplish that objective, a vehicle of the kind referred toin the introduction is characterized in that a light source for emittinga light beam to an optical waveguide disposed adjacent the light sourceis provided, said optical waveguide being provided with an input surfacefacing towards the light source for inputting at least part of the lightbeam from the light source, as well as with at least one output surfacefor outputting a light beam that is being passed through the opticalwaveguide to the license plate and/or the at least one tail light.Preferably, the light source(s) of the tail light(s) will illuminate—viathe optical waveguide—the license plate, whereas in the alternative thelight source(s) of the license plate will illuminate—via the opticalwaveguide—the tail light(s) of the vehicle. It is also possible that thelight source(s) are located elsewhere, i.e. not being the lightsource(s) of the tail light(s) or the license plate. The opticalwaveguide in particular comprises at least two output surfaces, of whichone output surface outputs part of the light beam that is being passedthrough said optical waveguide to the license plate and of which theother output surface outputs part of the light beam that is being passedthrough said optical waveguide to the tail light. As a result of thisarrangement it is no longer necessary to provide separate lamps for eachfunction, viz. tail light(s) and rear license plate lights, as waspreviously the case, but one or more lamps function both as the taillight(s) and as the license plate lights. Thus, a lamp may emit a lightbeam, part of which is directly used for the tail light, whilst anotherpart is passed to the license plate via the optical waveguide for thepurpose of illuminating said license plate. According to anotherpossibility, the light beam emitted by the lamp is passed both to thetail light and to the license plate via the optical waveguide. In allthe above cases, the tail lights and the license plate lights are turnedon and off simultaneously.

International patent publication no. WO 99/06760 (SDL, Inc.) discloses avehicle with a plurality of individually addressable semiconductor laserlight sources each producing a beam of light, wherein said light sourcesare optically coupled to fiber optic waveguides. The laser light sourcesare grouped together at a single location within the vehicle for easyaccess and conveniently located within the vehicle. Said fiber opticwaveguides distally transmit the light beams to the brake lights, taillights, instrumentation lights and indicator lights of the vehicle. Adisadvantage of this known vehicle is that each laser light must beindividually switched on or off, with all electrical complicationsinvolved, whereas quite a number of fiber optic waveguides are necessarywithin the vehicle. Furthermore, a central location of the group oflaser lights is found to be cumbersome and even undesirable in practice,particularly when said location is damaged in the event of a collision.

In one preferred embodiment of the vehicle according to the invention,the optical waveguide is disposed in part in front of the license plate.In particular, the part of the optical waveguide that is disposed infront of the license plate is transparent.

In another preferred embodiment of a vehicle according to the invention,the part of the optical waveguide that is disposed in front of thelicense plate comprises means for directing the light beam that is beingoutput from the output surface towards the license plate. Such opticaldirecting means in particular comprise a mirror or a lens.

In another preferred embodiment of a vehicle according to the invention,the optical waveguide is arranged in part near a transversal orlongitudinal edge of the license plate. Also in this case, the part ofthe optical waveguide that is disposed near the edge of the licenseplate particularly comprises means (in particular mirrors or lenses) fordirecting the light beam that is being output from the output surfacestowards the license plate.

In another preferred embodiment of a vehicle according to the invention,the vehicle comprises at least two tail lights. Particularly, the twotail lights each comprise a lamp which lamps, for example, alsoilluminate the rear license plate via the optical waveguide. In anotherpreferred variant, a lamp is used which provides the light for the taillights as well as for the license plate via the optical waveguide.

In another preferred embodiment of a vehicle according to the invention,the light source comprises a LED (light emitting diode). It is possiblethen to use red LEDs and white LEDs close together, the red LEDs beingused for the tail lights and the white LEDs being used for illuminatingthe license plate, all via the optical waveguide.

The invention also relates to an optical waveguide suitable for use in avehicle according to the invention.

The invention will be explained in more detail hereinafter withreference to FIGS. illustrated in a drawing, in which:

FIGS. 1 and 2 are schematic side elevations of a first and a secondembodiment of a lighting system for use in the vehicle according to theinvention;

FIG. 3 is a plan view of the lighting system of FIG. 2;

FIGS. 4 and 5 are schematic side elevations of a second and a thirdembodiment of a lighting system for use in a vehicle according to beinvention;

FIG. 6 is a schematic side elevation and bottom view of coupled opticalwaveguide components; and

FIG. 7 is another bottom view of coupled optical waveguide components.

FIG. 1 shows a lighting system which comprises a tail light 1 providedwith a light source 2 in the form of a LED (light emitting diode), forexample, and a reflector 1 for reflecting a light beam emitted by theLED rearwards in the direction of traffic coming up from behind. Anoptical waveguide 4 is disposed adjacent the LED. The optical waveguide4 has an input surface 5 facing towards the LED for inputting part ofthe light beam from the LED, as well as an output surface 6 foroutputting the part of the light beam that is being passed through theoptical waveguide to a license plate (not shown).

FIG. 2 shows a lighting system similar to the system that is shown inFIG. 1, with corresponding parts being indicated by the same numerals,with this understanding that the optical waveguide 4 consists of twoportions 4′ and 4″. The portion 4′ has an input surface 5 for inputtingthe light beam from the LED and an output surface 6′ for outputting (bymeans of mirrors 7) part of the light beam that is being passed throughthe optical waveguide portion 4′ to the tail light 1. The opticalwaveguide portion 4″, which is mounted in line with the opticalwaveguide portion 4′, likewise has an output surface 6″ for guiding andsubsequently outputting part of the light beam that is being passedthrough the optical waveguide portion 4′ to the license plate 8. Theoptical waveguide portion 4″ is in part mounted in front of the licenseplate 8.

FIG. 4 corresponds to FIG. 3, with corresponding parts being indicatedby the same numerals, with this understanding that the portion 4″ of theoptical waveguide 4 is in part disposed near a longitudinal edge of thelicense plate 8. Again, mirrors 7 are used for directing the light beamthat is being output from the output surface 6″ towards the licenseplate 8.

FIG. 5 shows a lighting system in which a light source 2 is positionedcentrally between the portions 4′, 4″ of the optical waveguide 4, inwhich the light source 2 is further bounded by mirrors 7 for the purposeof passing a light beam emitted by the light source 2 through theoptical waveguide portions 4′, 4″ in the direction of the tail light 1on the one hand and of the license plate 8 on the other hand, and thatwith minimal losses.

FIG. 6 shows two coupled portions 4′, 4″ of the optical waveguide 4 inside elevation and in bottom view, respectively. The coupled portions4′, 4″ comprise an overlapping portion 9 for inputting a light beamemitted by the light source 2 via the overlapping portion in anefficient manner. FIG. 7 shows a bottom view of another design ofpartially overlapping portions 4′, 4″ of the optical waveguide 4.

It is noted that the invention is not limited to the illustratedembodiments, but that it also extends to other variants that fall withinthe scope of the appended claims.

1. A vehicle fitted with at least one tail light and a rear licenseplate to be illuminated, characterized in that a light source foremitting a light beam to an optical waveguide disposed adjacent thelight source is provided, said optical waveguide being provided with aninput surface facing towards the light source for inputting at leastpart of the light beam from the light source, as well as with at leastone output surface for outputting a light beam that is being passedthrough the optical waveguide to the license plate and/or the at leastone tail light.
 2. A vehicle according to claim 1, wherein the opticalwaveguide comprises at least two output surfaces, of which one outputsurface outputs part of the light beam that is being passed through saidoptical waveguide to the license plate and of which the other outputsurface outputs part of the light beam that is being passed through saidoptical waveguide to the tail light.
 3. A vehicle according to claim 1,wherein the optical waveguide is in part disposed in front of thelicense plate.
 4. A vehicle according to claim 3, wherein the part ofthe optical waveguide that is disposed in front of the license plate istransparent.
 5. A vehicle according to claim 3, wherein the part of theoptical waveguide that is disposed in front of the license platecomprises means for directing the light beam that is being output fromthe output surface towards the license plate.
 6. A vehicle according toclaim 1, wherein the optical waveguide is arranged in part near an edgeof the license plate.
 7. A vehicle according to claim 6, wherein thepart of the optical waveguide that is disposed near the edge of thelicense plate particularly comprises means for directing the light beamthat is being output from the output surfaces towards the license plate.8. A vehicle according to any one of the claim 1, wherein said vehiclecomprises at least two tail lights.
 9. A vehicle according to claim 1,wherein said light source comprises a LED (light emitting diode).
 10. Anoptical waveguide suitable for use in a vehicle according to claim 1.